body {
  font-family: 'Segoe UI', sans-serif;
  text-align: center;
  background: linear-gradient(to bottom, #f0f4f8, #cce0f0);
  padding: 30px;
}
h1 {
  margin-bottom: 20px;
  color: #2a5d9f;
}
.board {
  display: grid;
  grid-template-columns: repeat(3, 100px);
  grid-template-rows: repeat(3, 100px);
  gap: 10px;
  justify-content: center;
  margin: 0 auto 20px;
}
.cell {
  background: white;
  font-size: 2.5em;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 3px solid #007acc;
  border-radius: 10px;
  box-shadow: 0 2px 5px rgba(0,0,0,0.2);
  cursor: pointer;
  transition: background 0.3s, transform 0.2s;
}
.cell.taken {
  cursor: not-allowed;
  color: #333;
}
.cell:hover:not(.taken) {
  background: #e6f2ff;
  transform: scale(1.05);
}
#status {
  font-size: 20px;
  font-weight: bold;
  min-height: 24px;
  color: #2a2a2a;
}
#restart {
  padding: 10px 20px;
  font-size: 16px;
  background-color: #007acc;
  color: white;
  border: none;
  border-radius: 5px;
  cursor: pointer;
}
#restart:hover {
  background-color: #005fa3;
}